Refutation: Paul and Jesus use "brothers" for all believers, but Matthew names four brothers of Jesus including James — confirmed by Josephus

Paul does use "brothers" for all believers (Romans 14:13) and Jesus does the same (Matthew, Luke). But Matthew explicitly names four brothers of Jesus including James, and Paul says he met James on multiple occasions (Galatians). Josephus (a non-Christian) also confirms James was executed as the brother of Jesus. Multiple independent sources — Paul, Matthew, Josephus — all identify James as Jesus's biological brother.